With today’s tracking-enabled telescopes, digital cameras, and computer software, amateur astronomers are doing more useful work than ever before. Such was the case with Jupiter: it appears that a large object has just struck the surface of the planet. That’s similar to what happened in 1994 with comet Shoemaker-Levy–on the exact date of the 15th anniversary of that impact, in fact, not to mention the 40th anniversary of the Apollo landing.

Space.com reports that while NASA tracked the impact, the initial call came from Anthony Wesley of Murrumbateman, Australia, who told NASA he noticed a new dark “scar” suddenly appear on Jupiter early Friday between 6 a.m. and 12 p.m. EDT.

“I’d noticed a dark spot rotating into view in Jupiter’s south polar region and was starting to get curious,” Wesley wrote on his observation blog. “When first seen close to the limb (and in poor conditions) it was only a vaguely dark spot, I thought likely to be just a normal dark polar storm. However as it rotated further into view, and the conditions also improved, I suddenly realized that it wasn’t just dark, it was black in all channels, meaning it was truly a black spot.”

Wesley used a 14.5-inch reflector on an equatorial mount for his observations, as a separate New York Times article reports. NASA scientists are still studying the images to figure out what it was that hit Jupiter. (Image credit: Anthony Wesley)